I've read this thread with interest, and I'm sure QF is working to get the right balance between all the issues.
To declare my interest, I'm a SFSC who pays for QP access from his own pocket. I have the benefit of membership to a corporate program for State Government employees which gives me access at a discounted annual rate. I won't disclose that rate however, as I might have things thrown at me.
In smaller volume ports, lounge crowds aren't that much of an issue. It's only in the majors (capital city ports) where this has become a real problem at some times of the day.
I commented on another thread that the MEL T1 QP has over 5,000 people pass through its doors a day. While its not the biggest lounge on the network, I've been there at all times of the day and never really struggled to get a seat. I have the same experience with SYD T3.
Having said that, there are limited options for expanding lounges at these ports without massive capital expenditure. I'm sure there's super bean counters and business analysts who weigh up all the issues to determine if it makes economic and passenger sense - and maybe the numbers aren't there yet to justify the required outlays to expand SYD/MEL any further.
For ports however like CBR & PER T2, there is capacity issues. We all know PER T2 is being addressed as we speak, and CBR will no doubt be rectified as part of the major upgrades happening to the terminal.
Also, I don't see the commoditisation of QFF having much of a bearing on lounge occupancy levels. The fact is while there's been tonnes of new members to the program, unless they're accruing points hand over fist they're unlikely to be in the lounge.
And when they are, they're in either the J or F lounges (where available) as they've upgraded their tickets using points, or acquired a full reward ticket on same. And even still, the amount of money paid for their points, a portion of the ticket said points are used for are more than likely fed back into the Lounges balance sheets anyway, because access is publicised as a benefit of flying in that class - so they have to fund it.
Similar has already been mentioned on the subject of frequent travellers, who have a lot of spend with the airlines and there is value to be gained by offering complimentary lounge access to them.
As already mentioned, paid lounge access increases revenue for the airline. I can say that because of the lounge access I have, I'm more likely to fly QF as it gives me an integrated product and comfort level from end to end. My number of flights annually has increased exponentially since joining QP, and while not enough to hit PS (yet), I'm flying an average of 15 sectors a year, mainly domestic. This is a 200% increase on my previous flying patterns just three years ago.
Provision of, expansion, occupancy and access to lounges is always going to be a contentious issue for all concerned. Its about finding balance, and in my personal experience I haven't found this to be much of an issue.